To study structure-acitivity relationships in the apomorphine molecule and in related systems, with respect to emetic effects and other pharmacological properties. To gain further insight on the role of apomorphine and of certain other systems which are congeners and fragments of the apomorphine molecule, as agonists capable of exerting dopaminergic effects, especially insofar as these effects bear upon emetic activity and upon possible value of these compounds as anti-Parkinsonian agents and as dilators of the renal vascular bed. In addition, thse compounds will be explored for other pharmacological actions, and the metabolism of these agents will be investigated.